Long baseline interferometry: a promising tool for multiplicity investigations of massive stars

Massive binaries are crucial laboratories that allow us to investigate processes occurring in quite extreme conditions, such as particle acceleration, high-energy emission, or even dust formation. All these processes are intimately dependent on binarity. Our understanding of the underlying physics strongly requires preliminary multiplicity studies likely to uncover still undetected binaries, and determine their orbital parameters. However, classical spectroscopic approaches sometimes fail to provide a solution to this issue. Long baseline interferometry turns out to be a promising complementary technique to address the question of the multiplicity of massive stars. A campaign has been initiated with the VLTI to take benefit of this technique.